The son of Democratic congressman Jim Moran of Virginia has resigned from his father’s campaign after an undercover video shows him discussing a plan to cast fraudulent ballots.

Patrick Moran had been a field director for his father’s campaign. He said Wednesday he didn’t take the man seriously and humored him, adding that he should have walked away.

An organization led by activist James O’Keefe, Project Veritas, released a video showing an undercover operative pitching a voter-fraud plan to Patrick Moran. The plan called for casting ballots in the names of 100 voters who were registered but rarely voted.

In the video, Patrick Moran expresses doubts about the plan but eventually tells the undercover volunteer to “look into it.”